Sizing



made.

Patented July 20, 1943 SIZING Edgar W. Spanagel, Wilmington, DeL,assignor to u Pont de Nemours & Company, Wilmington, Del., a corporationof Delaware No Drawing. Application September 21, 1940, Serial No.357,757

24 Claims. (01. 26032) This invention relates to new sizing compositionswhich are suitable for use on knitting yarns composed of syntheticlinear polyamides.

For along time silk has dominated the sheer, full-fashioned hosieryfield. Relatively recently, a class of synthetic yarns, prepared from aclass of materials known as synthetic linear polyamides, has come to beused for sheer, full-fashioned hosiery. The preparation of this type ofmaterial and the production of yarn from the material are described inU. S. Patents Nos. 2,071,250, 2,130,523 and 2,130,948. The termsynthetic linear polyamide as used throughout the specification andclaims is intended to refer specifically to the material disclosed inthe aboveidentified patents. The preparation of sheer, knit ladiesfull-fashioned stockings from this type of yarn is described in U. S.Patents Nos. 2,157,116 and 2,157,119. The knitting of ladies sheerstockings from yarns of synthetic linear polyamides created new andserious problems in the satisfactory sizing of such yarns. Without anysize these yarns, when knitted into sheer, full-fashioned stockings andsubsequently handled, developed an undesirably large proportion ofpulled threads. For years, the art has been confronted with a similarproblem in the knitting of sheer stockings from ingrain silk. Theknitting of sheer stockings from ingrain silk produces stockings a verylarge proportion of which have pulled threads; and because this problemwas never solved ingrain silk stockings are seldom There has been nosizing problem for silk in the gum because of the presence of a naturalprotecting coat of sericin over .the silk filaments.

When the word "sizing is used, it does not refer to the application ofoils, finishes, dressings,

and the like, but is restricted to the narrower,

meaning of the word; namely, the application of an adhesive coating toprotect the filaments in the knitting operation and in the course ofhandling the fabric subsequent to the knitting operation.

Sizes have been developed for the warp sizing of artificial silk yarns;e. g., viscose rayon, cellulose acetate, etc. It is also well known thatartificial silks require no size for tricot knitting or circularknitting. Hence, the problem of sizing these yarnshas been concernedalmost entirely with the preparation of the yarns for weaving. It is,therefore, evident that prior to the introduction of the syntheticlinear polyamide yarns into the field of sheer hosiery knitting, therewas no problem of sizing knitting yarns. It is equally true that priorto that time, no sizing composition had been developed which wassatisfactory for use in knitting sheer hosiery when applied to syntheticlinear polyamide yarns.

The requirements for a, good warp size for weaving yarns are much lessrigorous than the requirements for a good size for yarns to be used inthe knitting of sheer, full-fashioned hosiery. Furthermore, therequirements for a satisfactory size for use on yarns composed ofsynthetic linear polyamides are much more critical than for sizes to ,beused on previously known artificial filaments or natural fibers.Therefore, a satisfactory size for synthetic linear polyamide yarns forknitting full-fashioned hosiery must possess all of the followingcharacteristics:

1. The size must protect the fabric from snags and pulled threads. Afull-fashioned stocking fabric is sheer and delicate. It is subjected toa considerable amount of handling after the knitting operation; for itmustbe looped, seamed, stitched, inspected, and preset before it isdyed. The rough hands of operators cause entirely too many pulledthreads if the size does not give good protection.

, 2. The size must adhere well and bind the filaments together duringtwisting, coning and other textile operations and perform well duringand following the knitting operation. The action of the knitting needlesand sinkers on the sized yarn is so drastic as to cause flaking 01f ofthe size with resultant loss of protection if the size does not adhereextremely well. Since synthetic linear polyamide filaments are spunsubstantially round and smooth and synthetic linear polyamides aremarkedly insensitive to water, the problem of size adherence is muchgreater than it is for relatively water-sensitive yarns such as viscoserayon, cotton, etc.

3. The sized yarn mustrun well on the knitting machine; that is, afterpassing through the dip trough, it must not stick to the guides andsnappers following a shut-down of the machine and size must notaccumulate on the needles and sinkers. Sticking on the guides andsnappers causes press-offs when the machine is started up again.Accumulation on the needles and sinkers eventually causes holes and runsin the fabric if the accumulation becomes severe.

4, The size must soften sufiiciently on passing through the dip troughto enable the formation of regular stitches of uniform size and tocement the loops together when the fabric dries. If the size softensinsufliciently, poor stitch formation and poor snag resistance result.on the other hand, if it softens too much, the

- edges as it comes oi! the knitting machine, the

fabric is diiiicult to seam and the cost of production increases; alsotheseams are likely to be bulky and crooked.

6. The size must be readily removable in an aqueous boil-oil. bathbefore dyeing. It is generally desirable, though not always necessary,to remove the size before dyeing the fabric. It is much more economicalto remove the size with water than with some other solvent.

7. The size should be free from any tendency to cause corrosion orabrasion of the various parts of the knitting machines which the yarncontacts.

The problem of developing a size which will fulfill these rigorousrequirements is relatively new in the field of synthetic yarnproduction. Many different sizing compositions have been developed foruse on rayon yarns, and many of these sizes have been tried withsynthetic linear polyamide yarns; but all ofethemany sizing compositionstried have been found to lack one or more of the above requirements tosuch a great extent as to render impossible their use in sizingsynthetic linear polyamide yarns for the knitting of full-fashionedhosiery. Even the recently developed polyvinyl alcohol sizes which haveproven to be very useful for the sizing of rayon and other weaving yarnshave failed to satisfy the rigorous requirements for a good size forsynthetic linear polyamide yarns used in the knitting of full-fashionedhosiery. These sizes are, in general, toowater-sensitive. They becomesticky and collect on the knitting machine parts. In an eifort toincrease the viscosity alcohol-boric acid sizes, or polyvinyl alcoholde-' of polyvinyl alcohol sizes, it has been suggested degree by reasonof a gelling action on the polyvinyl alcohol. The addition of borax andother agents to polyvinylalcohol sizes has failed to improve them foruse on synthetic linear polyamide yarns This highly viscous, boraxmodifled polyvinyl alcohol composition, when applied to synthetic linearpolyamide yarn, flakes off of the polyamide yarn very badly, giving verypoor running properties.

It is, therefore, an object of the present invention to furnish animproved type of textile sizing composition particularly suitable forsizing synthetic linear polyamide knitting yarns to be used in theproduction of sheer, full-fashioned hosiery.

It'is a further object of the present invention to furnish an improvedmethod of sizing :textile yarn, particularly synthetic linear polyamideknitting yarns to be used in the production of sheer, full-fashionedhosiery.

A specific object of the invention is to provide of being successfullyknitted into full-fashioned hosiery.

Other objects of the invention willbecome apparent hereinafter.

It has now been found that excellent sizing compositions, which are.suitable for the sizing of synthetic linear polyamide yarns tobe used inknitting sheer, full-fashioned hosiery, can be prepared from polyvinylalcohol, or a watersensitive derivative of polyvinyl alcohol, and

boric acid. These new sizing compositions, characterized by a lowviscosity and consequent high degree of solubility and ease ofapplication, adhere well to the smooth, round polyamide filaments, bindthe filaments together well, impart to the yarn good running propertieson full-fashioned lmitting machines, protect the full-fash ionedstocking fabric well from snags and runs, prevent serious edge rollingof the full-fashioned stocking fabric, and are readily removed byhotwater.

It has been further found that these polyvinyl rivative-boric acid sizeswill adhere to synthetic linear polyamide yarn better if an anchor coat(or a sub-coat) of tannic acid is applied to the yarn before applyingthe size. The tannic acid apparently adheres very well to the syntheticlinear polyamide and also tojthe size. However, it has been found thatthe adherence of the size to the yarn is improved by the tannic acidonly if the tannic acid coat is applied first and that a single mixtureof the two applied in one step does not produce a well-sized yarn havinggood full-fashioned hosiery knitting properties, nor does theapplication of a coat of tannic acid on top of a coat of the sizeproduce a sized yarn having good full-fashioned hosiery knittingproperties. The proper ratio of tannic acid in the anchor coat to thesize coat imparts astonishingly good snag resistance and runningproperties to yarn sized in accordance with the preferred method ashereinafter described. Moreover, it has been found that the tannic acidanchor coat decreases the water-sensitivity of the size coat sumcientlyto make possible conditioning of the sized polyamide yarn over water.This is very advantageous because of the practical ease ofcontrollingsuch a conditioning process. The use of 'tannic acidunder-coatings in polyethylene oxide (polyethylene glycol), which servesas a plasticizing agent. This polyethylene oxide is a polymerizationproduct obtained from ethylene oxide and preferably has a molecfreedomfrom flaking on, use of the polyethylene oxide plasticitd size with orwithout an I anchor coat of tainic acid is particularly ada sized,synthetic linear polyamide yarn capable vantageous for yarn that is tobe. twisted after the sizing operation. The use of polyethylene oxide asa plasticizing agent in a water-sensitive hydroxylated polyvinyl resinsizing composition is the invention of D. E. Strain and is described andclaimed in the co-pending application, Ser. No. 357,755 died of evendate herewith.

The following examples are given to illustrate preferred sizingcompositions and preferred methods of applying the same. The-details setforth in the examples are not, however, to be considered as limitativeof the invention. The percentages set forth in the examples designatepercentages by weight.

} Examplel A skein of 30-denier, 10-filament, ISO-tum polyhexamethyleneadipamide yarn is sized by soaking the skein of yarn in a solutioncomprising 8% of partially saponifled polyvinyl acetate having asaponification number of 140 and a viscosity of centipoises in a 4%aqueous solution at 20 C.,' 1.7% boric acid, and 90.3% water. The skeinis removed from the bath-and centrifuged to remove excess solution. Itis then dried, wound on to a bobbin, and finally coned, applyingapproximately 5% olive oil in the coning operation. The yarn knits wellon a fullfashioned hosiery knitting machine. It does not stick to theknitting needles or knitting machine guides when wet in the customarysilk knitting method. There is no appreciable accumulation of the sizeon the needles and sinkers of the knitting machine. The knitted fabrichas good snag resistance and is not subject to objectionable edge rollcharacteristics.

Example II The size is readily removed by washing the fabric in hotwater.-

acid. After drying, the yarn is sized with a solution comprising 7.5%partially saponifled polylution, then dried, and soaked in a solution ofpartially saponified polyvinyl acetate and boric acid such as isdescribed in Example I. The skein is removed from the size bath,centrifuged, and dried. The yarn is wound on to a bobbin and from thebobbin to a cone, applying about 5% teaseed oil tothe yarnr. The yarnknits well on a. full-fashioned knitting machine, does not flake off,and does not stick to the parts of the knitting machine. The size isremoved from the yarn by washing the fabric in hot water; the size ismore easily removed from the yarn by adding a small amount of soap or asmall amount of alkali to the washing water.

Example III A skem of 30-denier, lu-filament, 30-turnpolyhexamethylenesebacamide yarn is sized, dried, and coned in accordance with the methodoutlined in Example I. The sized yarn has good knitting and snagresisting characteristics.

Example. I V

Ezample V A BO-denier, 10-filament, 2-turn yarn prepared fro-mpolyhexamethylene adipamide is put on' an uptwister and given 28 turnsadditional vinyl acetate having a saponlflcation number of approximatelyand a viscosity of approximately 5 centipoises in a 4% aqueous solutionat 20 C., 1.6% boric acid, and approxmately 90.9% water. The size isapplied on-the-run in a machine constructed much like a coning machine,but having a bobbin as the windup package. The size is applied bypassing the yarnover a rotating roll dipping into a trough containingsize solution. Sizing is carried out in a room having 50% relativehumidity at 88 F. The size dries sumciently before being wound up toprevent sticking or wicking.- Three percent of size is applied. The yarnis coned while applying 3.5% of olive oil. The resulting yarn is foundto knit well on a standard full-fashioned-knitting machine. The size isremoved by washing the fabric in a hot water solution containing 0.1%hydrated trisodium phosphate, 0.1% oxalic acid, and 0.5% fatty alcoholsodium sulfate.

Example VI Fifty parts of a composition comprising 10%triethanolamine'oleate, 20% crude lauryl alcohol and 70% olive oil; areemulsified in 50 parts of a solution of 4% dipotassium phosphate inwater. The eniulsification may be accomplished by slowly dropping theoil phase into the water phase while vigorously stirring with a highspeed stirrer followed by several passes through a colloid mill.

The resulting oil emulsion is applied to a yarn coated first with tannicacid and then sized as in Example V. The oil emulsion is applied duringthe coning operation by means, of a rotating roll dipping in the oilemulsion; Approximately 4% of the oil is applied. The resulting yarn hasexcellent knitting properties even though conditioned at a high relativehumidity. The size and the coning oil are readily removed by washing thefabric in hot water.

Example VII Yarn sized as in Example V is coned while applying 5%, of aneutral vegetable oil. This yarn is conditioned over water and knittedin the usual manner with the yarn passing through a water dip or a waterwick prior to going through the carrier tube. The water dip has to 4 ofdipotassium phosphate added to it. This alkaline treatment improved theknitting properties of the yarn and decreases the number of press-offsand holes in the knitted fabric. The size is readily removed from thefabric by washing in hot water.

Example VIII twist while applying a 25% boat of tannic acid fashionedknitting machine.

good.

' Example IX of a low viscosity polyvinyl alcohol (obtained by"completely saponifying polyvinyl acetate) with 170 cc. of 37%formaldehyde and 16 cc. of concentrated hydrochloric acid to 75-80 C.with stirring during 3-4. hours, neutralizing with monia (using methylred as indicator), and mixing 200 grams of this solution with 50 gramsof a 5% aqueous solution of boric acid and 125 grams of water. The sizedyarn was air-dried and twist set in an oven at 160 F. wet bulb, 170 F.dry bulb. The yarn was coned and knit on a full- The size ran well onthe knitting machine with very little deposit and the knitted fabric hadgood snag resistance. The partial formal of this example hadapproximately 20% of formal.

Example X Ninety-six ends of a 30-denier, l5-fllament, 30-tumpolyhexamethylene adipamide yarn were taken from a magazine creel,formed into a warp with ends /4 of an inch apart, sized with a 24 inchapplication roll, dried in a 14 foot drier at finally wound up onindividual packages on a chain quiller. The size composition contained8% of a low viscosity partial acetate of polyvinyl alcohol, 1.6% boricacid, and approximately 90.4% water. The yarn speed was 300 feet perminute. The R. P. M. of the size application roll was 9. Approximately6% of size was applied to the yarn. After drying, the yarn was conedwhile applying a teaseed coning oil. The yarn was knit on afull-fashioned hosiery knitting machine. The stitch formation,edge-rolling characteristics, and snag-resistance were Example XISeventy parts of a 10% solution of a low viscosity partially hydrolyzedpolvinyl propionate (saponification No. 132) were mixed with 1.4 partsof boric acid dissolved in 28 parts of water. Vigorous agitation andcooling was necessary to produce a clear solution. This size solutionwas applied to a 30-denier, lo-fllament, 30-twist polyhexamethyleneadipamide yarn by means of a size roll using a yarn speed of 1,000 feetper minute. The yarn after being allowed to dry overnight at a relativehumidity of 50% at 25 was found to contain 4.58% size. The sized yarnwas knit on a 45 gauge full-fashioned hosiery knitting machine. No sizeaccumulated upon the needles of the knitting machine during theknitting. The yard delivered freely from the cones and did not tend tostick to the needles. The width of the fabric was satisfactory, and therolls at the edge were not tight. The snag resistance of the knittedfabric was good.

Example XII upon the needles of the knitting machine, and 75 of thefabric were not tight.

a size roll in the usual manner.

0 gave 3.99% size.

there was no indication of stickinesson the needles or poor deliveryfrom the cones. The snag resistance was of thesame order as that of theknitted fabric described in Example In.

Example XIII A size solutionysimilar to that of Example :1, was preparedusing 10% of boric acid basedon the partially hydrolyzed polyvinylpropionate.

10 The concentration of thepolyvinyl alcohol derivative in the solutionwas again 7%. A 80- denier, lo-filament, 30-twist polyhexamethyleneadipamide yarn was sized with this solutionat 1,000 feet per minute, thesize being applied with The yarn was found to contain 2.32% of size. Theyarn was knit on a 45 gauge full-fashioned hosiery machine. The siushowed a negligible tendency to accumulate .on the needles, and theknitted fabric was of good snag resistance.

In contrast to the above results. yarn sized with partially hydrolyzedwater-soluble polyvinyl propionate of .the same saponitlcation numherand the same viscosity, but without boric acid, accumulated badly uponthe needles of the knittingmachine and also stuck to the needles. Thewidth of the fabric was not nearly as satiswere tight.

100 C., oiled with a second 24 inch roll and 'Emmple XIV A size wasprepared by mixing together a solution of 0.54 parts of boric acid with36 parts of I water and 54 parts of a 10% solution of a etherifiedpolyvinyl alcohol glycolic acid ether 35 sodium salt of mediumviscosity. The boric acid 0 1,000 feet per minute. The size was appliedby means of a size roll. The yarn was then coned with teaseed oil andknit. The yam delivered freely from the cones, did not stick-to theneedies, and the size showed only a very slight tendency to accumulateupon the needles.

The snag resistance of the knitted fabric was very good while thewidth'and edge roll characteristics were satisfactory. Analysis of thesized yarn Example xv A size solution, similar to that of Example XIV,was prepared using the same quantity of the same polyvinyl alcoholglycolic ether sodium salt with 1.62 parts of boric acid dissolved in 35of water were added to bring the viscosity down to 9, figurecorresponding to that of the above polyvinyl alcohol glycolic ethersodium salt size.

A 30-denier, lo-filament, 30-twist polyhexamethylene adipamide yarn wassired with this solution at 1,000 feet per minute, the size beingapplied by means of a size roll. Analysis showed the yarn to contain2.08% size. The yarn was co'ned with teaseed oil and knit on a 45 gaugefullfashioned hosiery machine. The yarn delivered 7 freely from thecones, did not stick to the needles, and exhibited a negligible tendencyto accumulate upon the needles. The snag resistance of the knittedfabric was moderately good, while the width was satisfactory.

The rolls at the edge Similar yarn was also sized withdzhe sodium saltof the same polyvinyl alcohol glycolic ether sodiumsalt withoutmodification with boric acid. The size accumulated so badly on theneedles that knitting was impossible.

Example XVI A resin was prepared by-dissolving 300 grams of partiallysaponified polyvinyl acetate, having a saponiflcation number of to 15and a viscosity in 4,% aqueous solution at 25 C. of to 6 centipoises, in1,700 grams of H20 and adding 24 grams of isobutyraldehyde and 8 cc. ofconcentrated I-ICl to the solution. The mixture was heated for 3 hourson a steam bath with stirring and then cooled and filtered. Two hundredgrams of this solution were neutralized to methyl red with KOH and thenmixed with 90 grams of 5% boric acid and 85 grams oi. water. A 30-denier, 10-filament, 30-turn polyhexamethylene adipamide yarn was sizedwith this size on our single position bobbin-to-bobbin sizer at a windupspeed of 1,500 feet per minute, and a size roll speed of 10 R. P. M. Thesized yarn was twistset in a 170 F. dry bulb, 160 F. wet bulb oven for1.5 hours and was then coned with the application of teaseed oil. Sizedid not accumulate on the knitting machine during knitting and the knitfabric had a. good snag resistance.

The present invention broadly contemplates the preparation of sizes frompolyvinyl alcohol and water-sensitive derivatives of polyvinyl alcoholtogether with boric acid. Such sizes are generally suitable for sizingof synthetic linear polyamide yarn which is to be used in the knittingof sheer full-fashioned hosiery. Thus, watersensitive polyvinylcompounds in which 1% to 50%, and preferably to 50%, of the carbon atomsof the polyvinyl chain are attached to hy droxyl groups (such compoundsbeing hereinafter referred to as hydroxylated polyvinyl resin) whentreated with boric acid produce very desirabl yarn sizes.

The water-sensitive derivatives of polyvinyl alcohol which have givenparticularly good results are the partial esters of polyvinyl alcoholsuch as the partial acetates, the partial propionates, the glycolic acidesters, the partial formates, and the partial lactates; the partialethers of polyvinyl alcohol such as the glycol ethers, the glycolic acidethers, the methyl ethers, and the ethyl ethers, and including also. thepartial acetals of polyvinyl alcohol such as the partial formal, thepartial acetal, the partial glyoxal, the partial propional, and thepartial butyral, and including also the partial ketals of polyvinylalcohol such as ethyl-methyl ketal.

Likewise, water-sensitive derivatives of polyvinyl alcohol produced byinterpolymerization of polyvinyl esters with small proportions of othercomponents such as vinyl chloride, methyl methacrylate, methacrylic acid(produced by saponification), maleic anhydride, methyl vinyl ketone andunsymmetrical dichloroethylene will be suitable for use in theproduction of sizes in accordance with the present invention bytreatment with boric acid.

In general, anyone skilled in the art can readily determine the degreeof substitution on the polyvinyl alcohol and the per cent of boric acidrequired to produce a water-sensitive compound and to give optimumsizing properties. None of the above named derivatives, when usedwithout boric acid, are suitable for use in the sizing of syntheticlinear. polyamide knitting yarn, since they will not impart theretoasatisfactory snag resistance and good running properties on theknitting machine.

The partial acetate esters, and the partial formals, of polyvinylalcohol, when used in 'ac-, cordance with the practice of thisinvention, have given outstanding results in sizing synthetic linearpolyamide full fashioned hosiery. knitting yams.

Although partially saponified or hydrolyzed polyvinyl acetates havingsaponiflcation numbers fromv to 145 and viscoslties from 4 to 6centipoises in 4% solutions at 20 0. modified with 20% to 22.5% boricacid (based on th weight of the polyvinyl acetate) are particularlyuseful for sizing synthetic linear polyamide full-fashioned hosieryknitting yarns, numerous other partially saponified polyvinyl acetatesand various mixtures and combinations thereof lie within the scope ofthe present invention.

Partially saponified polyvinyl acetates having saponification numbers ofbetween 10 and 300, or even somewhat lower than 10 or higher than 300,may be used to advantage in sizing synthetic linear polyamide yarnswhich are to be used in the knitting of sheer, full-fashioned hosiery.For better and more-consistent results, however, it is much to bepreferred to use a; partially saponifled polyvinyl acetate having asaponification number between 40 and 220.

The saponification I number of the partially saponiiied polyvinylacetate, as used herein, is defined as the number of milligrams ofpotassium hydroxide required to completely saponify one gram of thepartially saponifled polyvinyl acetate sample.

The term "partially saponified polyvinyl acetate is intended to includepolyvinyl acetate which has been partially hydrolyzed by saponificationwith alkali or by any other means.

Partially saponiiied polyvinyl acetates having viscosities from 1.5 to20 centipoises in a 4% solution at 20 C. are usefulinaccordance withthis invention. The viscosity should be determined on a 4% aqueoussolution at 20 C.. using a Hoeppler viscosimeter (manufactured byGebrueder Haake, Medingen, Germany).

The water-sensitive hydroxylated polyvinyl resins are preferably used insolutions containing from 3% to 12% of the resin.

As above indicated, the partial formals of polyvinyl alcohol-are alsoparticularly useful. Formals of polyvinyl alcohol containing 10% to 30%of formal and having 5% to 20% of boric acid, based on the weight of theformal, are preferred.

Although particularly desirable results are obtained with sizescomprising a water-sensitive hydroxylated polyvinyl resin and boric acidwhen the boric acid used constitutes approximately 20% to 22.5% of theweight of the said polyvinyl resin, it should be understood that boricacid may be used with the Water-sensitive hydroxylated polyvinyl resinsin the preparation of sizes containing other proportions of boric acid.The amount ofboric acid required to give good running properties hasbeen found to vary with the particular hydroxylated polyvinyl resinused. To obtain the bestresults, the amount of boric acid to be usedwill vary between 5% and 25%, based on the weight of the said resin. Oneskilled in the art can formulate sizes with increasing amounts of boricacid and readily determine the optimum concentration.

Using a, polyvinyl acetate having a saponification number of and noother agent for reducing its water-sensitivity, at least 10% boric acidis generally required to give fair running properties. With a polyvinylacetate having a saponification number of 234 only 12.5% boric acidgives desirable results, but. this is practically all the boricacid thatthis partially saponified polyvinyl acetate will tolerate withoutprecipitating from solution: Likewise, with polyvinyl acetate having asaponification number of 140 and 10% aluminum acetate as an auxiliaryagent. it is possible to reduce the boric acid concentration to 10% andstill retain fair running properties. The use of less than boric-acidwith the hydroxylated polyvinyl resin. has never given sizes with veryattractive running properties except when using a tannic acidundercoating. It

is, therefore, to be understood that in practicing this invention.proportions ofboric acid up to the limit of the tolerance 01 thepolyvinyl material may be used in preparing the sizing composition.

The limit of tolerance of the polyvinyl material for the boric acid isthat percentage 01 boric acid based on the weight of the polyvinylmaterial which-can be barely tolerated by the polyvinyl material withoutcausing the polyvinyl material to gel or precipitate. The gelling orprecipitating of the polyvinyl material is an indication that the limitof tolerance oi the boric acid has been exceeded. a I

It is, of course, within the scope of this invention to apply to theyarn coats of size of various percentages other than those specificallydisclosed above. It isalso within the scope or the invention to applytwo or more coats of these sizes to the yarn. Furthermore. a coat of awater-sensitive hydroxylated polyvinyl resin size can be applied over acoating of another size which by itself is insufllcient for the purposesof the present invention.

As above indicated, it is desirable to provide the yarn with an anchorcoat or tannic acid prior to the application of the partially saponifledpolyvinyl acetate-boric acid size. It should be understood that tannicacid, gallic acid, digallic acid or any of the various tannins, whenused as an anchor coat in the sizing of a yarn in accordance with thepresent invention, lie within the scope of this invention and are c'onsidered to be included by the term tannic acid. as used in thespecification. Good results are obtained with 0.02% to 1.5% coats oftannic acid; and particularly good results are obtained when 0.05% to0.3% coats of tannic acid are applied to the yarn; but the anchor coatis not to be considered to be limited to these percentages. It will beapparent that numerous similar anchoring compounds may be useful assub-coats on yarns to the end of more eflectively binding the sizecomposition to the yarn. In view of the new and very great problem ofeffecting adherence of a size to a rela- 'tively water-insensitive yarn.such as synthetic linear polyamide yarn, the principle of using ananchor coat in the sizing of yarn is an outstanding improvement.

While the invention has been described with reference to the applicationor the water-sensitive hydroxylated polyvinyl resin coat from watersolution, it is obvious that it can be applied from solutionscontainingother solvents; Similarly, it will be apparent that .theanchor coat and the size coat can be applied to the yarn by other meansand in other waysthan' those described above;' namely, skein immersiontreatment and continuous applicationbypassing the yarn over a size roll.dippi w into the soluflOn,

While these sizing compositions may be applied to the yarn in anyconvenient manner, it is pre-' ierred for reasons of economy andexcellence of product to apply these sizes in some tom of continuousoperation. When the sizes are being applied in such a manner, it isimportant that these size solutions be given sufiicient time tothoroughly impregnate the yarn before drying. This may be accomplishedby arranging that the yarn be given suflicient air travel in anatmosphere oi high relative humidity before being wound up, or,preferably, the sizedyarn may be wound up directly on some form ofbobbin while still wet and then b allowed to dry on the bobbin. Thislatter procedure will, insure that the yarn dries slowly enough so thatthorough penetration occurs. This sizing process is further describedand claimed in co-pending application Serial No. 369,951, filed December13, 1940.

Although polyethylene oxide having a molecular weight 01' approximately4,000 is preferred as a plasticizer for the hydroxylated polyvinylresins of this invention, it is to be understood that polyethyleneoxides of other molecular weights can be used and the better results areobtained with polyethylene oxides having molecular weights fromapproximately 282 to approximately 10,000. However, the use of otherpolyethylene oxides is not to be considered as excluded from the scopeof this invention. It will be apparent, of course, that otherconcentrations Such oils as oxidized linseed oils having iodine numbersbetween and 105, China-wood oil, castor oil, etc., will be found to beuseful in conjunction with the sizes oi! this invention. Such oils maybeapplied as emulsionsin water or in solutions in various solvents, suchas ethyl alcohol, isopropyl alcohol, butyl alcohol, methyl, ethyl orbutyl Cellosolve," etc. It will be apparent that the drying oil may beemulsified in the size composition or that it may be applied to the yarnin a separate step.

The use of an alkaline after-treatment in connection with the sizingprocess of this invention has been disclosed above. The alkalinetreatment tends to gel the surface 01 the size coat giving good runningproperties to the yarn. The alkaline after-treatment may be applied innumerousways by treating the yam-with vapors or solutions or alkalinesubstances. By alkaline substance is meant any substance which, whenshaken with water, gives an alkaline reaction to the water.

The sizes of this invention may be modified with solutions ordispersions of various modifying agents for various purposes. Forexample, polymethacrylic acid or polymethacrylates may be used asmodifying agents to improve the run- Various other plasticizers, suchasglycerol, the

various slycols, sorbitol, glucose, diethylene glycol, triethyleneglycol, ethanol formamide, glyc erol glycollate, ethanol acetamide,tetraethylene glycol, dimethoxytetraethylene glycol, etc-., may be usedwith these sizes. Various lubricants, such as mineral oil, olive oil,teaseed oil, other vegetable oils, sulfonated mineral oils andsulfonated based on the weight of the yarn, affording good ethanolamineand its fatty acid ester, diglycol oleate, morpholine, pyridine, etc.,may be coated over these sizes either alone or mixed with a coning oilor finishing agent. It will be apparent that many of the materials whichmay be added to the sizing compositions, or applied to the sized yarn,may serve more than one purpose, for example, the same material mayserve as a plasticizer and also as a lubricant, or as a plasticizer anda preservative.

Although the invention has been discussed with particular reference tomultifilament yarns of synthetic linear polyamides, it will be obviousthat the same compositions will be applicable as sizes to othersynthetic linear polyamide structures, such as monofils, films,'staplefibers, spun yarn, mixed yarn, ribbon, etc. Various structures possessto a greater or smaller extent, as the case may be, essentially the samecritical sizing problems as the multifilament polyamide yarns; for thesmoothness and lack of water-sensitivity of the synthetic linearpolyamides prevent the close adherence of the conventional sizes to thepolyamide structure.

Although the sizing compositions of this invention are unique andoutstanding for the sizing of synthetic linear polyamide yarns which areto be used in the knitting of sheer hosiery, they will also be useful inthe sizing of other yarns and fabrics, such as cotton, silk, Wool,linen, viscose rayon, cuprammonium rayon, cellulose acetate rayon, yarnprepared fromfsynthetic linear vinyl polymers and synthetic linearethylene polymers, etc.; although the problem of adherence of the sizeto the yarn is not nearly so great in the case of these other types ofyarn. These sizes will be found to be particularly useful for sizingyarns which are relatively water insensitive. It will also be obviousthat these sizing compositions may be useful for sizing yarns to be usedin weaving operations as Well as knitting operations.

The sizes of this invention present the distinct advantage over theprior art sizes of adhering well to synthetic linear polyamide yarnwhile possessing other qualities desired in a sizefor yarn to be used inthe knitting of sheer hosiery.

Yarns sized with the sizes of this invention and in accordance with theprocess of this invention knit very well, and produce sheer,full-fashioned stocking fabrics which are relatively free of snags andpulled threads. These sizes minimize edge rolling characteristics andthus assist in the more economical production of sheer, knit,full-fashioned hosiery. The sizes of this invention cause very littlewear and corrosion of the needles and sinkers of the knitting machines.In knitting yarn sized in accordance with this invention, the stitchformation is very good and may be maintained uniform over long periodsof time.

comparatively small amounts of these sizes are effective in protectingthe multifilament polyamide yarn, 2% to 8% by weight of the size,

protection. Since the size is easily removed from the yarn and there isnot so much loss in weight of the fabric resulting from the removal ofthe size, polyamide yarns sized in accordance with this invention areinuch more desirable, for instance, in mixed fabrics with celluloseacetate rayon and other synthetic yarns than is natural silk. Naturalsilk has approximately 20% to 24% sericin; hence, the boil-off ofnatural silk results in a great loss in weight of the fabric and theremoval of the sericin size is so diflicult that it not infrequentlycauses considerable damage to cellulose acetate rayon or other syntheticfibers present in a fabric mixed with naturalsilk.

Since it is obvious that many changes and modifications can be made inthe above-described details without departing from the nature and spiritof the invention, it is to be understood that the invention is not to belimited to the de tails described herein except as set forth in theappended claims.

I claim:

1. A yarn sizing composition comprising a hydroxylated polyvinyl resinand 5%-25% boric acid based on the weight of the resin, said resin beingsufliciently water-sensitive to be readily removable from a yarn withhot water.

2. A yarn sizing composition comprising an aqueous solution of ahydroxylated polyvinyl resin and 5%-25% boric acid based on the weightof the. resin, said resin being sufficiently watersensitive to bereadily removable from a yarn with hot water.

3. A yarn sizing composition containing from 3%-12% of a hydroxylatedpolyvinyl resin and 5%-25% boric acid based on the weight of the resin,said resin being sufficiently water-sensitive to be readily removablefrom a yarn with hot water. i

4. A yarn sizing composition comprising a hydroxylated polyvinyl resinin which 1%-50% of the carbon atoms of the polyvinyl chain are.attachedto hydroxyl groups and 5%-25% boric acid based on the weight of theresin, said resin being sufficiently water-sensitive to be readilyremovable from a yarn with hot water.

5. A yarn sizing composition comprising boric acid and a partial esterof polyvinyl alcohol, said boric .acid being present in a quantity from5%-25% of the weight of the resin; said resin being sufficientlywater-sensitive to be readily removable from a yarn with hot water.

6. A yarn sizing composition comprising boric 'acid and 3%-12% of apartial ester of polyvinyl alcohol, said boric acid being present in aquantity of 5%25% of the weight of the resin, said resin beingsufficiently water-sensitive to be readily removable from a yarn withhot water.

'7. A yarn sizing composition comprising a partially saponifiedpolyvinyl acetate and 5%-25% boric acid based on the weight of theacetate.

8. A yarn sizing composition comprising a partial formal of polyvinylalcohol and 5%-25% boric acid based on the weight of the formal.

9. A yarn sizing composition comprising an aqueous solution of apartially saponified polyvinyl acetate and 5%-25% boric acid based onthe weight of the acetate.

10. A yarn sizing composition comprising an aqueous solution containingbetween 3%-12% of a partially saponifiedv polyvinyl acetate and 5%-25%boric acid based on the weight of the acetate.

11. A yarn sizing composition. comprisingfan' aqueous solutioncontaining a partially saponie fled polyuinyl acetate and %-25% boricacid basedon the weight or the acetate, said polyvinyl acetate, having asaponiflcation number of between 40 and 220.-

12. A\ yam sizing composition comprising an aqueous solution containinga partially saponiiied' polyvinyl acetate and 5%-25% boric acid basedasa'geoi tures =0: diamine with dibasic carboxylic acid. said yamsuitable for use in the knitting of sheer,

from at least one of the groups consisting of (a)monoaminomonocarboxylic acids, and (b) mixtures of diamine with dibasiccarboxylic acid, said yarn suitable for use in the knitting of sheer,full-fashioned hosiery, containing a coating of 'a size comprising ahydroxylated polyvinyl resin and 5%-25% boric acid, said resin beingsufficiently water-sensitive to be readily removable from a yarn withhot water.

14. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymer-forming composition which comprises insubstantial amount reacting material selected from at least one of thegroups consisting of (a) monoaminomonocarboxylic acids, and (b) mixturesof diamine with dibasic carboxylic acid, said yam suitable foruse in theknitting of sheer, full fashioned hosiery,-containing from 3%--12% of ahydroxylated polyvinyl resin and 5%-,25% boric acid based on the weightoi'the resin, said resin being sufliciently water-sensitive to bereadily removable from a yarn with hot water.

15.- A yarn composed of a "linear polyamide comprising the reactionproduct of a linear polymet-forming composition which comprises insubstantial amount reacting material selected from at least one of thegroupsconsisting of (a) 'monoaminomonocarboxylic acids, and (b) mixtures"or diamine with dibasic carboxylic acid, said yarn suitable for use inthe knitting of sheer full-fashioned hosiery, containing a coating oi! asize comprising a hydroxylated polyvinyl resin in which 1%50% of thecarbon atoms of the polyvinyl chain are attached to the hydroxyl groups,and 5%-25% boric acid based on the weight of the resin, said resin beingsufficiently water-sensitive to be readily removable from a yarn withhot water.

16. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymer-forming composition which comprises insubstantial amount reacting material selected from at least one of thegroups consisting oil (a) monoaminomonocarboxylic acids, and (b)mixtures of diamine with dibasic carboxylic acid,

full-fashioned hosiery, containing a coating of a size comprising boricacid and 3%-12% or a partial ester of polyvinyl alcohol, said boric acidbeing present in a quantity of 5% -25% based on the weight of the resin,said resin being suiilciently water-sensitive to be readily removablefrom a yarn with hot water.

18. A yarn composed of a linear polyamide comprising thereaction'product of a linear pol mer-i'orming composition whichcomprises in substantial amount reacting material selected from at leastone of the groups consisting of (a) monoaminomonocarboxylic acids, and(b) mix-- tures of diamine with dibasic carboxylic acid, said yarnsuitable for use in the knitting of sheer, full-fashioned hosiery,containing a coating of 'a' size comprising partially saponifledpolyvinyl said yarn suitable for use in the knitting of sheer,

full-fashionedhosiery, containing a coating of a size comprising boricacid and a partial ester 01' polyvinyl alcohol, said boric acid beingpresent in a quantity of 5%-'25% based on the weight of the. resin, saidresin being sufliciently watersensitive to be readily removable from ayarn with hot water.

17. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymer-forming composition which comprises insubstantial amount reacting material selected from at least one of thegroups consisting of (a) monoaminomonocarboxylic acids, and (b)mixacetate and 5%-25%' boric acid based on the weight of the acetate.

19. A yam composed of a linear polyamide comprising the reaction productof a linear polytrier-forming composition which comprises in substantialamount reacting material selected from at least one of the groupsconsisting of (a) monoaminomonocarboxylic acids, and (b) mixtures ofdiamine with dibasic carboxylic acid,

,said yarn suitable for use in the knitting of sheer,

full-fashioned hosiery, containing a coating of a size comprisingpartially saponifled polyvinyl acetate and 5%-25% boric acid based onthe weight of the acetate, said polyvinyl acetate having asaponification number between 40 and 220.

20. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymar-forming composition which comprises insubstantial amount reacting material selected from at least one of thegroups consisting Of (a)' monoaminomonocarboxylic acids, and (72)mixtures of diamine with dibasic carboxylic acid, said yarn suitable foruse in the knitting of'sheer, full-fashioned hosiery, containing acoating of a size comprising partially saponiiied polyvinyl acetate and5%-25% boric acid based on the weight 01 the acetate, said polyvinylacetate having a viscosity of between 1.5 and 20, centipoises in a 4%water solution at 20 C.

21. A yarn sizing composition comprising boric acid and a partial etherof polyvinyl alcohol, said boric acid being present in a quantity from5%25% of the weight of the resin, said resin being suflieientlywater-sensitive to be readily re- 1 movable from a yarn with hot water.

22. A yarn sizing composition comprising boric acid and 3%-12% of apartial ether of polyvinyl alcohol, said boric acid,being present in aquantity of 5%-25% of the weight of the resin, said resin beingsufllciently water-sensitiv to be readily removable from a yarn with hotwater.

a 23. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymer-i'orming composition which comprises insubstantial amount reacting material selected from at least one of thegroups consisting of (a) monoaminomonocarboxylicacids, and (b) mixturesof diamine with dibasic carboxylic acid, said yarn suitable for use inthe knitting of sheer. full-fashioned hosiery, containing a coating of asize comprising boric acid and a. partial ether of polyvinyl alcohol,said boric acid being present in a quantity of 5%-25% based on theweight of the resin, said resin being sufllciently watersensitive to bereadily removable from a yarn with hot water.

24. A yarn composed of a linear polyamide comprising the reactionproduct of a linear polymer-iorming composition which comprises insubstantial amount reacting material selected from at least one o! thegroups consisting of (a) monoaminomonocarboxylic acids, and (b) mix- Itures of diamine with dibasic carboxylic acid,

said yam suitable for use the knitting of sheer,

full-fashioned hosiery, containing a coating of a size comprising boricacid. and 3%-.-12% of a partial ether of polyvinyl alcohol, said boricacid being present in a quantity of 5%-25% based on .the weight of theresin. said resin being sumciently water-sensitive to be readilyremovable from a yarn with hot water.

EDGAR W. SPANAGEL.

